Backlight unit and display device using the same

ABSTRACT

Disclosed is a backlight unit and a display device using the same, which includes a first reflector, a second reflector  300  and at least one light source module  100  disposed between the first and second reflectors, wherein a back surface of the first reflector comprises an inclined plane  201  and a flat surface  202 , with facing the second reflector, and the inclined plane is adjacent to the light source and the flat surface is extended from an end of the inclined plane, with the inclined plane and the flat surface being collinear.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation application of prior U.S. patentapplication Ser. No. 14/097,444 filed Dec. 5, 2013, which is aContinuation application of prior U.S. patent application Ser. No.13/363,052 filed Jan. 31, 2012, which claims priority under 35 U.S.C.§119 to Korean Application No. 10-2011-0075995 filed on Jul. 29, 2011,whose entire disclosures are hereby incorporated by reference.

BACKGROUND

1. Field

Embodiments may relate to a backlight unit and a display device.

2. Background

Generally, a conventional display device may include a liquid crystaldisplay (LCD), a plasma display panel (PDP) and the like.

Different from the PDP that is self-luminescent, the LCD is notself-luminescent and it requires a backlight unit as a self-luminescent.

Such a backlight unit used in the LCD may be categorized into an edgebacklight unit and a direct backlight, based on location of a lightsource. In the edge type, light sources are disposed on right and leftlateral surfaces or up and down lateral surfaces of an LCD panel. Lightmay be dispersed to a front surface by a light guide plate uniformly.Because of that, the edge backlight unit has good uniformity of lightand it may enable the panel ultra-thin.

The direct backlight unit is used for a 20-inch-or-more display. In thedirect backlight unit, light sources are disposed on a backside of apanel. Because of that, the direct backlight unit has an advantage ofbetter luminous efficiency than the edge backlight unit and it is usedfor a large display requiring high brightness.

A cold cathode fluorescent lamp (CCFL) is used for the light source ofthe conventional edge backlight unit or the direct backlight unit.

However, an electric voltage is applied to the backlight unit using theCCFL constantly and the amount of used electricity is increased. TheCCFL has a disadvantage of approximately 70% of color reproduction,compared with a cold cathode fluorescent lamp (CCFL) and anotherdisadvantage of environmental pollution because of mercury addedthereto.

To solve such disadvantages, there have been actively in progressstudies on a backlight unit using a light emitting diode (LED)substituting for the CCFL.

In case of using the LED for the backlight unit, a partial on/off of LEDarrays may be enabled and power consumption may be reduced remarkably. ARGB LED exceeds 100% of color production specifications of NationalTelevision System Committee (NTSC) and a more vivid image quality may beprovided to a consumer.

The above references are incorporated by reference herein whereappropriate for appropriate teachings of additional or alternativedetails, features and/or technical background.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described in detail with reference to thefollowing drawings in which like reference numerals refer to likeelements wherein:

FIG. 1 is a sectional view illustrating a backlight unit according to anembodiment;

FIGS. 2A to 2C are sectional views illustrating a structure of a firstreflector shown in FIG. 1;

FIG. 3 is a sectional view illustrating a location of a flat surface ofthe first reflector;

FIGS. 4A to 4C are sectional views illustrating the first reflectorincluding a specular-reflection region;

FIGS. 5A and 5B are sectional views illustrating a boundary regionbetween an inclined plane and a flat surface possessed by the firstreflector;

FIGS. 6A and 6B are sectional views illustrating the thickness of thefirst reflector;

FIGS. 7A and 7B are sectional views illustrating the width of an uppersurface possessed by the first reflector;

FIGS. 8A and 8B are sectional views illustrating a projection projectedfrom the upper surface of the first reflector;

FIGS. 9A to 9D are sectional views illustrating a reflection patternformed in the first reflector;

FIGS. 10A to 10C are sectional views illustrating the length of thefirst reflector;

FIGS. 11A to 11D are sectional views to explain an arrangement relationbetween a light source module and each of first and second reflectors;

FIGS. 12A to 12C are sectional views illustrating a second reflectorincluding a slope side and a flat surface;

FIGS. 13A to 13C are sectional views illustrating a second reflectorincluding a plurality of inclined planes;

FIG. 14 is a diagram illustrating a backlight unit having opticalmembers disposed therein;

FIG. 15 is a diagram illustrating a display module including thebacklight unit according to the embodiment; and

FIGS. 16 and 17 are diagrams illustrating a display device according toan embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments will be described with reference to the annexeddrawings.

It will be understood that when an element is referred to as being ‘on’or ‘under’ another element, it can be directly on/under the element, andone or more intervening elements may also be present.

When an element is referred to as being ‘on’ or ‘under’, ‘under theelement’ as well as ‘on the element’ can be included based on theelement.

FIG. 1 is a sectional view illustrating a backlight unit according to anembodiment.

As shown in FIG. 1, the backlight unit may include a light source module100, a first reflector 200 and a second reflector 300.

Here, the light source module 100 may be located between the firstreflector 200 and the third reflector 300. Here, the light source module100 may be adjacent to the first reflector 200.

In some cases, the light source module 100 may be spaced apart apredetermined distance from the second reflector 300, simultaneously incontact with the first reflector 200. Alternatively, the light sourcemodule 100 may be spaced apart a predetermined distance from the firstreflector 200, simultaneously in contact with the second reflector 200.

Alternatively, the light module 100 may be spaced apart a predetermineddistance from the first reflector 200 and the second reflector 300 or itmay be in contact with the first reflector 200 and the second reflector300.

The light source module 100 may include a substrate having an electrodepattern and at least one light source disposed on the substrate.

Here, the light source of the light source module 100 may be a top viewtype light emitting diode.

Alternatively, the light source may be a side view type light emittingdiode.

The substrate may be a printed circuit board (PCB) formed of a selectedmaterial from polyethylene terephtalate (PET), glass, polycarbonate (PC)and silicon (Si), or the substrate may be a film.

Alternatively, the substrate may be a unilayered PCB, a multilayeredPCB, a ceramic substrate or a metal core PCB selectively.

Here, a reflection coating film or a reflection coating material layermay be formed on the substrate and the substrate may reflect the lightgenerated from the light source toward a central region of the secondreflector 300.

The light source may be a light emitting diode (LED) chip and the lightemitting diode chip may be configured of a blue LED chip, an ultravioletlight LED chip or it may be configured of a package combined with one ormore of red, green, blue, yellow green and white LED chips.

The white LED may be realized by combining a yellow phosphor on the blueLED or combining a red phosphor and a green phosphor on the blue LED, orby using a yellow phosphor, a red phosphor and a green phosphor on theblue LED simultaneously.

Next, the first reflector 200 and the second reflector 300 may be facingeach other, spaced apart a predetermined distance, to have air guidebetween them.

The first reflector 200 may be formed of a reflection coating film or areflection coating material and it may reflect the light generated fromthe light source module 100 toward the second reflector 300.

Here, a back surface of the first reflector 200 may face the secondreflector 300, with an inclined plane and a flat surface.

At this time, the inclined plane may be adjacent to the light sourcemodule 100 and the flat surface may be extended from an end of theinclined plane, with being located at the collinear position withrespect to the light source module 100.

The inclined plane of the first reflector 200 may be inclined apredetermined angle downwardly from a top surface of the first reflector200. The flat surface of the first reflector 200 may be in parallel tothe top surface of the first reflector 200.

Here, the inclined plane of the first reflector may be a concavesurface, a convex surface or a flat surface.

The reason why the predetermined area of the back surface disposed inthe first reflector 200 may be the inclined plane is that a hot spot ofa light-entry region, the size of the first reflector 200 can be reducedby the first reflector 200 reflecting the light toward the secondreflector 300. Because of that, a bezel region may be reducedadvantageously.

The inclined plane may be disposed in a predetermined region of thefirst reflector 200 and the first reflector 200 may include a metalmaterial or a metal oxide, with a high reflectivity, such as aluminum(Al), silver (Ag), gold (Au) and titanium dioxide (TiO2).

A saw-toothed reflection pattern may be formed in a predetermined regionof the back side of the first reflector 200.

Here, the reflection pattern may be a flat surface or a curved surface.

The reason why the reflection pattern is formed in the predeterminedregion of the first reflector 200 is that brightness may be increased ina central region of the backlight unit by reflecting the light generatedfrom the light source module 100 toward the central region of the secondreflector 300.

An inclined plane may be formed in a predetermined region of the secondreflector 300 and the second reflector 300 may include a metal materialor a metal oxide, with a high reflectivity, such as Al, Ag, Au and TiO2.

The inclined plane may be aligned with at least one of the light sourcemodule 100 and the first reflector 200.

Here, the inclined plane of the second reflector 300 may be inclined apredetermined angle with respect to the surface of the first reflector200 and it may be at least one of concave, convex and flat surfaces.

In some cases, the second reflector 300 may include at least oneinclined plane and at least one flat surface. The flat surface of thesecond reflector 300 may be in parallel to the flat surface of the firstreflector 200.

Furthermore, the second reflector 300 may include at least two inclinedplanes with at least one inflection point. The curvatures of first andsecond inclined planes adjacent to each other with respect to theinflection point may be different from each other.

FIGS. 2A to 2C are sectional views illustrating the structure of thefirst reflector shown in FIG. 2.

As shown in FIGS. 2A to 2C, the back surface of the first reflector 200may include a first region adjacent to the light source module 100 and asecond region adjacent to the first region.

Here, the first region may be an inclined plane 201 and the secondregion may be a flat surface 202.

The inclined plane 201 of the first region may be inclined apredetermined angle along downward direction of the first reflector 200and the flat surface 202 of the second region may be in parallel to thetop surface of the first reflector 200.

At this time, the flat surface 202 of the second region may be extendedfrom an end of the inclined plane 201, and the flat surface 202 and thelight source module 100 may be collinear.

In case of FIG. 2A, the inclined plane 201 of the first reflector 200may be a concave surface with a predetermined curvature.

In case of FIG. 2B, the inclined plane 201 of the first reflector 200may be a convex surface with a predetermined curvature. In case of FIG.2C, the inclined plane 201 of the first reflector 200 may be a flatsurface with a predetermined inclined angle.

FIG. 3 is a sectional view illustrating arrangement of the flat surfacedisposed in the first reflector.

As shown in FIG. 3, the light source module 100 may include a substrate102 and at least one light source 101 disposed on the substrate 102.

Here, the light source 101 may have a top surface with a first width(W1) and the flat surface 202 of the first reflector 200 may be disposedin a center of the first width (W1) of the light source 101.

If the flat surface 202 of the first reflector 200 is disposed beyondthe center (in an upper area) of the width (W1) of the light source 101,a hot spot may be generated in the light-entry region.

If the flat surface 202 of the first reflector 200 is disposed under thecenter of the first width (W1) (in a lower area of the width) of thelight source 101, the light might be blocked or brightness might bedegraded entirely.

As a result, if the flat surface 202 of the first reflector 200 isdisposed within the first width (W1), the hot spot may be reduced in thelight-entry region and the size of the first reflector 200 may bereduced. Because of that, the bezel region of the display panel may bereduced advantageously.

In addition, the inclined plane 201 of the first reflector 200 may havea second width (W2) and the flat surface 202 of the first reflector mayhave a third width (W3).

Here, the second width (W2) of the inclined plane 201 may be identicalto or different from the third width (W3) of the flat surface 202.

For example, the second width (W2) of the inclined plane 201 may belarger than the third width (W3) of the flat surface 202.

FIGS. 4A to 4C are sectional views illustrating the first reflector thatincludes a specular-reflection region.

As shown in FIGS. 4A to 4C, the back surface of the first reflector 200may include a specular-reflection region to specular-reflect the lightor a scattered-reflection region to scattered-reflect the light.

In case of FIG. 4A, the back surface of the first reflector 200 mayinclude an inclined plane 201 and a flat surface 202. Both of theinclined plane 201 and the flat surface 202 may be thespecular-reflection regions.

In other words, a specular-reflection sheet may be disposed on theinclined plane 201 and the flat surface 202, to specular-reflect thelight.

In case of FIG. 4B, the back surface of the first reflector 200 mayinclude an inclined plane 201 and a flat surface 202. The inclined plane201 may be the specular-reflection region and the flat surface 202 maybe the scattered-region.

In other words, a specular-reflection sheet may be disposed on theinclined plane 201 to specular-reflect the light and ascattered-reflection sheet may be disposed on the flat surface 202 toscattered-reflect the light.

In case of FIG. 4C, the back surface of the first reflector 200 mayinclude an inclined plane 201 and a flat surface 202. The inclined plane201 may be a specular-reflection region and the flat surface 202 mayinclude a specular-reflection region and a scattered-reflection region.

In other words, a specular-reflection sheet may be disposed on theinclined plane 201 to specular-reflect the light. Thespecular-reflection sheet may be disposed on a predetermined region ofthe flat surface 202 and a scattered-reflection sheet may be disposed onthe other region to scattered-reflect the light.

Here, the full-reflection sheet disposed on the flat surface 202 may beadjacent to the inclined plane 201 or between specular-reflectionsheets.

If the specular-reflection sheet is disposed on the first reflector 200,more lights may be reflected to the second reflector 300. If thescattered-reflection sheet is disposed on the first reflector, the lightmay be transmitted to a region of the second reflector 300 having lowbrightness and the low brightness may be compensated.

FIGS. 5A and 5B are sectional views illustrating a boundary regionbetween the inclined plane and the flat surface of the first reflector.

As shown in FIG. 5A, the first reflector 200 may include an inclinedplane 201 and a flat surface 202 formed on the back surface thereof. Aboundary region between the inclined plane 201 and the flat surface 202may have a dihedral angle formed by them.

However, as shown in FIG. 5B, the boundary region between the inclinedplane 201 and the flat surface 202 may include a convex surface with apredetermined curvature.

The reason why the boundary region between the inclined plane 201 andthe flat surface 202 is the convex surface with the curvature isfollowing. If the dihedral angle is formed in the boundary regionbetween the inclined plane 201 and the flat surface 202, the incidentlight might be concentrated only on some region and overall brightnessmight fail to be uniform.

Because of that, the boundary region between the inclined plane 201 andthe flat surface 202 may be formed to be a convex surface with apredetermined curvature and uniform brightness may be provided.

FIGS. 6A and 6B are sectional views illustrating the thickness of thefirst reflector.

First of all, as shown in FIG. 6A, the first reflector 200 may include afirst region adjacent to the light source module and a second regionadjacent to the first region.

Here, a back surface of the first region disposed in the first reflector200 may have an inclined plane 201 and a top surface of the first regionmay have a flat surface.

Here, a flat surface formed in a top surface of the second region may bein parallel to a flat surface formed in a back surface of the secondregion.

At this time, in the first region, the thickness (t1) of a predeterminedarea adjacent to the light source module may be smaller than thethickness (t2) of an area distant from the light source module.

In the second region, the thickness of a predetermined area adjacent tothe light source module may be larger than the thickness (t4) of an areadistant from the light source module.

Also, in the top surface of the first reflector 200, the first regionmay be a flat surface and the second region may be a stepped surfacehaving two flat surfaces with different heights.

As shown in FIG. 6B, the first reflector 200 may include a first regionadjacent to the light source module and a second region adjacent to thefirst region.

Here, a back surface of the first region disposed in the first reflector200 may have an inclined plane 201 and a top surface of the first regionmay have an inclined plane.

In other words, the back and top surfaces of the first region may havethe same inclined planes, respectively.

A back surface of the second region disposed in the first reflector 200may have a flat surface 202 and a top surface of the second region mayhave a flat surface.

Here, the top surface of the second region may partially have aninclined plane and the flat surface of the top surface may be inparallel to the flat surface of the back surface.

At this time, in the first region, the thickness (t1) of an areaadjacent to the light source module may be the same as the thickness(t2) of an area distant from the light source module.

In the second region, the thickness (t3) of an area adjacent to thelight source module may be the same as the thickness (t4) distant fromthe light source module.

Also, in the top surface of the first reflector, the first region may bean inclined plane and the second region may be combined with an inclinedplane and a flat surface.

FIGS. 7A and 7B are sectional views illustrating the width of the topsurface of the first reflector.

First of all, as shown in FIG. 7A, the top surface of the firstreflector 200 may include a third region 203 adjacent to the lightsource module and a fourth region 204 adjacent to the third region 203.

Here, the third region 203 disposed in the top surface of the firstreflector 200 may be corresponding to the inclined plane disposed in theback surface of the first reflector 200 and the fourth region 204disposed in the top surface of the first reflector 200 may becorresponding to the flat surface disposed in the back surface of thefirst reflector 200.

Here, the third region 203 and the fourth region 204 may be flatsurfaces located on different lines.

In other words, the flat surface of the third region 203 may be higherthan the flat surface of the fourth region 204.

The width of the third region 203 may be different from the width of thefourth region 204.

That is, the width of the flat surface formed in the third region 203may be different from the width of the flat surface disposed in thefourth region 204. For example, the width of the flat surface disposedin the third region 203 may be larger than the width of the flat surfacedisposed in the fourth region 204.

That is because an active region of the display can be increased byreducing the width of the fourth region 204 and by reducing the width ofthe bezel accordingly.

In some case, the widths of the third and fourth regions 203 and 204 maybe the same.

As shown in FIG. 7B, the top surface of the first reflector 200 mayinclude a third region 203 adjacent to the light source module and afourth region 204 adjacent to the third region 203.

Here, the third region 203 disposed in the top surface of the firstreflector 200 may be corresponding to the inclined plane disposed in theback surface of the first reflector 200 and the fourth region 204disposed in the top surface of the first reflector 200 may becorresponding to the flat surface disposed in the back surface of thefirst reflector 200.

Here, the third region 203 may be a downwardly inclined plane and thefourth region 204 may be a flat surface in parallel to the back surface.

The width of the third region 203 may be different from the width of thefourth region 204.

In other words, the width of the flat surface disposed in the thirdregion 203 may be different from the width of the flat surface disposedin the fourth region 204.

That is because an active region of the display can be increased byreducing the width of the fourth region 204 and by reducing the width ofthe bezel accordingly.

In some cases, the widths of the third and fourth regions 203 and 204may be the same.

The third region 203 and the fourth region 204 disposed in the topsurface of the first reflector 200 may have the surfaces having the sameappearance. Alternatively, they may have surfaces having differentappearances, respectively.

The surfaces of the third and fourth regions 203 and 204 may be curvedor flat and they may be fabricated in various shapes rather than thecurved or flat shapes.

FIGS. 8A and 8B are sectional views illustrating a projection projectedfrom the top surface of the first reflector.

As shown in FIGS. 8A and 8B, the top surface of the first reflector 200may include at least one projection projected with a predeterminedheight.

In an embodiment shown in FIG. 8A, the top surface of the firstreflector 200 may include a third region 203 adjacent to the lightsource module and a fourth region 204 adjacent to the third region 203.The third and fourth regions 203 and 204 may have flat surfaces locatedon a different line, respectively.

Here, a first projection 211 and a second projection 212 may be disposedon the flat surface of the third region 203. A third projection 213 maybe disposed on the flat surface of the fourth region 204.

At this time, the height (h1) of the first projection 211, the height(h2) of the second projection 212 and the height (h3) of the thirdprojection 213 may be the same. In some cases, at least one of theheights (h1, h2 and h3) possessed by the first, second and thirdprojections 211, 212 and 213, respectively, may be the same.Alternatively, at least one of the heights (h1, h2 and h3) possessed bythe first, second and third projections 211, 212 and 213, respectively,may be different from the others.

In an embodiment shown in FIG. 8B, the top surface of the firstreflector 200 may include a third region 203 adjacent a fourth region204 adjacent to the third region 203. The third and fourth regions 203and 204 may have flat surfaces located on a different line,respectively.

Here, a first projection 211 and a second projection 212 may be disposedon the flat surface of the third region 203. A third projection 213 maybe disposed on the flat surface of the fourth region 204.

At this time, the height (h1) of the first projection 211, the height(h2) of the second projection 212 and the height (h3) of the thirdprojection 213 may be the same. In some cases, at least one of theheights (h1, h2 and h3) possessed by the first, second and thirdprojections 211, 212 and 213, respectively, may be the same.Alternatively, at least one of the heights (h1, h2 and h3) possessed bythe first, second and third projections 211, 212 and 213, respectively,may be different from the others.

Although not shown in the drawings, the first, second and thirdprojections 211, 212 and 213 may be employed to support or coupleoptical members or panel guide molds.

For example, the first and second projections 211 and 212 may be membersconfigured to be coupled with a panel guide mold to fix or support thedisplay panel. The third projection 213 may be a member to support theoptical members.

Here, a top surface of the third projection may be a convex surface witha predetermined curvature to reduce the contact area with the opticalmembers. As a result, the optical member may be protected from anexternal shock.

In some cases, a plurality of hollownesses or minute projections may befurther formed in the top surface of the third projection 213.

FIGS. 9A to 9D are sectional views illustrating a reflection patternformed in the first reflector.

As shown in FIGS. 9A to 9D, the first reflector 200 may include theinclined plane 201 and the flat surface 202 formed in the back surfacethereof. A plurality of reflection patterns 215 may be formed on theflat surface 202.

In FIG. 9A, the reflection pattern 215 may be saw-toothed and a surfaceof the reflection pattern 215 may be flat. In FIGS. 9B and 9C, thereflection pattern 215 may be saw-toothed and the surface of thereflection pattern 215 may be curved.

Here, in FIG. 9B, the surface of the reflection pattern 215 may beconcavely curved and in FIG. 9C, the surface of the reflection pattern215 may be convexly curved.

In some cases, as shown in FIG. 9C, the size of the reflection patterns215 may be getting larger from an end of the first reflector 200 towardthe other end thereof.

In other words, the size of the reflection pattern 215 may not beuniform. The size of a reflection pattern 215 close to the light sourcemodule may be larger than the size of another reflection pattern 215distant from the light source module.

The reason why the reflection patterns 215 are formed on the flatsurface of the first reflector 200 is that uniform brightness can beprovided by compensating brightness after reflecting the light towardthe region having relatively low brightness, compared with the otherregion.

As a result, such the reflection patterns 215 may be fabricated incorresponding regions, with various sizes according to the entirebrightness distribution of the backlight.

FIGS. 10A to 10C are sectional views illustrating the length of thefirst reflector.

As shown in FIGS. 10A to 10C, the second reflector 300 may include afirst region adjacent to the light source module 100 and a second regionadjacent to the third region.

The first region of the second reflector 300 may be aligned with thelight source module 100 and the first reflector and it may have a firstinclined plane inclined downwardly.

The second region of the second reflector 300 may be a flat surface inparallel to the flat surface disposed in the back surface of the firstreflector or it may include a second inclined plane inclined upwardly.

The back surface of the first reflector 200 may include an inclinedplane 201 adjacent to the light source module 100 and a flat surface 202adjacent to the inclined plane 201. The flat surface 202 disposed in theback surface of the first reflector 200 may be aligned in at least oneof the first and second regions disposed in the second reflector 300.

FIG. 10A illustrates an embodiment in that the flat surface 202 disposedin the back surface of the first reflector 200 is aligned in the firstregion of the second reflector 300. FIG. 10B illustrates an embodimentin that the flat surface 202 disposed in the back surface of the firstreflector 200 is aligned over the first region and the second region.FIG. 10C illustrates an embodiment in that the flat surface 202 disposedin the back surface of the first reflector 200 is aligned in the secondregion of the second reflector 300.

As mentioned above, the length of the first reflector 200 may bevariable according to various embodiments.

FIGS. 11A to 11D are sectional views illustrating an arrangementrelation between the light source module and the first and secondreflectors.

FIG. 11A illustrates the light source module 100 spaced apart apredetermined distance from the first and second reflectors 200 and 300.FIG. 11B illustrates the light source module 100 in contact with thefirst and second reflectors 200 and 300 simultaneously. FIG. 11Cillustrates the light source module 100 spaced apart a predetermineddistance from the second reflector 300, in contact with the firstreflector 200 simultaneously. FIG. 11D illustrates the light sourcemodule 100 spaced apart a predetermined distance from the firstreflector 200, in contact with the second reflector 300 simultaneously.

As shown in FIG. 11A, the light source module 100 may be spaced apart afirst distance (d1) from the first reflector 200 and a second distance(d2) from the second reflector 300.

Here, the first distance (d1) and the second distance (d2) may be thesame or different from each other.

For example, the first distance (d1) may be smaller than the seconddistance (d2).

If the first distance (d1) is larger than the second distance (d2), ahot spot may be generated.

As shown in FIG. 11B, the light source module 100 may be in contact withthe first reflector 200 and the second reflector 300.

Here, the light source module 100 may be in contact with the first andsecond reflectors 200 and 300, to prevent the hot spot and to transferthe light to a region distant from the light source 100 to reduce theoverall thickness of the backlight unit.

As shown in FIG. 11C, the light source module 100 may be in contact withthe first reflector 200 and it may be spaced apart a predetermineddistance (d) from the second reflector 300.

Here, the light source module 100 may be in contact with the firstreflector 200, to prevent the hot spot and to transfer the light to aregion distance from the light source module 100.

As shown in FIG. 11D, the light source module 100 may be in contact withthe second reflector 300 and it may be spaced apart a predetermineddistance (d) from the first reflector 200.

FIGS. 12A to 12C are sectional views illustrating the second reflectorincluding the inclined plane and the flat surface.

FIG. 12A illustrates the inclined plane of the second reflector 300 isflat and FIG. 12B illustrates the inclined plane of the second reflector300 is concavely curved. FIG. 12C illustrates the inclined plane of thesecond reflector 300 is convexly curved.

Here, a first region of the second reflector 300 may be the inclinedplane and a second region may be the flat surface.

FIGS. 13A to 13C are sectional views illustrating the second reflectorincluding a plurality of inclined planes.

In FIG. 13A, two neighboring inclined planes have flat surfaces,respectively. In FIG. 13B, two neighboring inclined planes haveconcavely curved surfaces and the curvatures of the two inclined planesmay be different from each other. In FIG. 13C, two neighboring inclinedplanes may have convex curved surfaces and the curvatures of the twoinclined planes may be different from each other.

As shown in FIGS. 13A to 13C, the second reflector 300 may include afirst region adjacent to the light source 100 and a second regiondistant from the light source module 100.

Here, the first region and the second region of the second reflector 300may be inclined planes.

In the meanwhile, a specular-reflection sheet may be formed on the firstregion of the second reflector 300 to specular-reflect the light. Atleast one of the specular-reflection sheet and scattered-reflectionsheet may be formed on the second region of the second reflector 300.

Here, the reason why the specular-reflection sheet is formed on thefirst region of the second reflector 300 is that uniform brightness canbe provided by reflecting more light toward the central region of thesecond reflector 300 having lower brightness.

Also, the reason why the scattered-reflection sheet is formed on thesecond region of the second reflector 300 is that the lower brightnesscan be compensated by scattered-reflecting the light in the secondregion of the second reflector 300 having the lower brightness.

The second reflector 300 may include a metal material or a metal oxidewith a high reflectivity such as Al, Ag, Au and TiO2. The materialsforming the first and second regions of the second reflector 300 may bedifferent from each other and surface roughness of the first region maybe different from surface roughness of the second region.

In other words, the first and second regions of the second reflector 300may be formed of the same materials, with a different surface roughness.

Alternatively, the first and second regions of the second reflector 300may be formed of different materials, and surface roughness of them maybe different from each other simultaneously.

In the meanwhile, the second reflector 300 may be a reflection coatingfilm or a reflection coating material layer having a reflection materialdeposited thereon.

The second reflector 300 may include at least one of a metal materialand a metal oxide. For example, the second reflector 300 may include ametal material or a metal oxide with a high reflectivity such as Al, Ag,Au and TiO2.

In this case, the second reflector 300 may be formed by depositing orcoating the metal material or the metal oxide on a polymer resin frame430 that is a bottom plate or it may be formed by printing metal ink.

Here, the depositing method may be thermal deposition, vapor depositionor vacuum deposition such as sputtering. The coating or printing methodmay be printing, gravure printing or silk printing.

In addition, the second reflector 300 may be a film or sheet and it maybe bonded on the polymer resin frame.

Here, the second reflector 300 may have the structure having a unilayerwith the uniform reflectivity formed on an entire region of the polymerresin frame that is the bottom plate. The second reflector 300 may havethe structure having multi-layers with different reflectivity,respectively, formed on the entire region of the polymer resin frame.

The reason why the second reflector 300 includes the multi-layers withthe different reflectivity is that the overall brightness of thebacklight might fail to be uniform because the light reflectivity of theoverall reflection surface is not uniform in case of forming only thereflection layer having the same reflectivity.

As a result, a reflection layer with a relatively high reflectivity maybe formed on a region with a high brightness in the reflection surfaceor a reflection layer with a relatively low reflectivity may be formedon a region with a higher brightness in the reflection surface. Becauseof that, the overall brightness of the backlight may be compensateduniformly.

FIG. 14 is a diagram illustrating a backlight unit having an opticalmember disposed thereon.

As shown in FIG. 14, an optical member 600 may be disposed, spaced aparta predetermined distance from the second reflector 300.

An air guide may be formed in the space between the second reflector 300and the optical member 600.

Here, an unevenness pattern 620 may be formed on a top surface of theoptical member 600.

The optical member 600 may be configured to disperse the light emittedfrom the light source module 100 and the unevenness pattern 620 may beformed to increase a dispersion effect.

In other words, the optical member 600 may be configured of a pluralityof layers and the unevenness pattern 620 may be disposed on theuppermost layer or a surface of one of the layers.

The unevenness pattern 620 may have a strip shape disposed along thelight source module 100.

At this time, the unevenness pattern 620 may include projected portionsprojected from the surface of the optical member 600 and each of theprojected portions may be configured of a first surface and a secondsurface facing each other. An angle formed between the first surface andthe second surface may be an acute angle or an obtuse angle.

In some cases, the optical member 600 may be configured of at least onesheet and it may selectively include a diffusion sheet, a prism sheet ora brightness enhancement sheet.

Here, the diffusion sheet may diffuse the light emitted from the lightsource and the prism sheet may guide the diffused light toward aluminescence region. The brightness enhancement sheet may enhancebrightness.

Furthermore, the second reflector 300 may include at least one of ametal material and a metal oxide. For example, the second reflector 300may include a metal material or metal oxide with a high reflectivitysuch as al, Ag, Au or TiO2.

Also, the second reflector 300 may be formed of a reflection coatingfilm or a reflection coating material layer and it may be employed toreflect the light generated in the light source module 100 toward theoptical member 600.

The second reflector 300 may have a saw-toothed reflection patternformed on a surface thereof facing the optical member 600. Thereflection pattern may be a flat surface or a curved surface.

The reason why the reflection pattern is formed on the surface of thesecond reflector 300 is that the light generated in the light sourcemodule 100 can be diffused and reflected uniformly.

According to the embodiments, the reflector for air guiding may includethe flat surface or the inclined plane. Because of that, the weight ofthe backlight unit may be reduced and the fabricating cost of thebacklight unit may be lowered. Also, the backlight unit may provideuniform brightness.

As a result, the economic feasibility and reliability of the backlightunit may be enhanced.

FIG. 15 is a diagram illustrating a display module including thebacklight unit according to the embodiments mentioned above.

As shown in FIG. 15, a display module 20 may include a display panel 800and a backlight unit 700.

The display panel 800 may include a color filter substrate 810 and athin film transistor substrate 820 (TFT) that are bonded to maintain auniform cell gap, facing each other. A liquid crystal layer (not shown)may be disposed between the two substrates 810 and 820.

A top polarization plate 830 and a bottom polarization plate 840 may bedisposed on and under the display panel 800, respectively. Morespecifically, the top polarization plate 830 may be disposed on a topsurface of the color substrate 810 and the bottom polarization plate 840may be disposed under the TFT substrate 820.

Although not shown in the drawings, gate and data driving parts may bedisposed in both sides next to the display panel 800 to generate adriving signal used to drive the panel 800.

FIGS. 16 and 17 are diagrams illustrating a display device according toan embodiment.

In reference to FIG. 16, a display device 1 may include a display module20, a front cover 30 and a back cover 35 surrounding the display module20, a driving part 55 disposed in the back cover 35 and a driving cover40 surrounding the driving part 55.

The front cover 30 may include a front panel (not shown) formed of atransparent material to transmit light. The front panel may protect thedisplay module 20, spaced apart a predetermined distance from thedisplay module 20, and transmit the light emitted from the displaymodule 20 to enable an image displayed on the display module 20 visibleoutside.

The back cover 35 may be coupled to the front cover 30, to protect thedisplay module 20.

The driving part 55 may be disposed on a surface of the back cover 35.

The driving part 55 may include a main control part 55 a, a main board55 b and a power supply part 55 c.

The driving control part 55 a may be a timing controller and it may bedriving part that adjusts an operation timing of each driver IC disposedin the display module 20. The main board 55 b may be a driving part thattransmits V-synch, H-synch and R, G and B resolution signals to thetiming controller. The power supply part 55 c may be a driving part thatapplies an electric voltage to the display module 20.

The driving part 55 may be disposed in the back cover 35 and it may besurrounded by the driving part cover 40.

A plurality of holes may be disposed in the back cover 35, to connectthe display module 20 and the driving part 55 with each other. A stand60 may be disposed in the back cover 35 to support the display device 1.

In contrast, as shown in FIG. 17, a driving control part 55 a of thedriving part may be disposed in the back cover 35 and the power board 55c of the main board 55 b may be disposed in the stand 60.

The driving part cover 40 may cover only the driving part 55 disposed inthe back cover 35.

In this embodiment, the main board 55 b and the power board 55 c may beindependently disposed or they may compose a single integration board,and this embodiment is not be limited thereto.

Another embodiment may be a display device, a pointing device or alighting system that includes the first and second reflectors and thelight source module described in the embodiments. For example, thelighting system may include a lamp and a streetlamp.

Such the lighting system may be used as a lighting lamp having aplurality of light emitting diodes focused thereon to generate light.Especially, the lighting system may be used as a downlight mounted in aceiling or wall of a building, with exposing an open portion of a shade.

The embodiments described above may include the reflector for air guidethat includes the inclined plane partially, without a light guide plate.The weight of the display device may be reduced and the fabrication costof the display device may be lowered. Also, the uniform brightness maybe provided.

As a result, the economic feasibility and reliability of the backlightunit may be enhanced.

Accordingly, the embodiments may provide a backlight unit and a displaydevice using the same.

In one embodiment, a backlight unit includes a first reflector; a secondreflector; and at least one light source module disposed between thefirst and second reflectors, wherein a back surface of the firstreflector may include an inclined plane and a flat surface, with facingthe second reflector, and the inclined plane may be adjacent to thelight source and the flat surface is extended from an end of theinclined plane, with the inclined plane and the flat surface beingcollinear.

The inclined plane of the first reflector may be inclined apredetermined angle toward the second reflector and the flat surface ofthe first reflector is in parallel to the top surface of the firstreflector.

The inclined plane of the first reflector may be at least one of aconcavely curved surface, a convexly curved surface and a flat surface.

The light source module may include a substrate, at least one lightsource disposed on the substrate, and the flat surface of the firstreflector may be located in a range of the width of the first reflector.

The width of the inclined plane may be the same as or different from thewidth of the flat surface.

The inclined plane and the flat surface may be specular-reflectionregions configured to reflect the light. Or, the inclined plane may be aspecular-reflection region configured to specular-reflect the light andthe flat surface may be a scattered-reflection region configured toscattered-reflect the light. Or, the inclined plane may be aspecular-reflection region and the flat surface may include thespecular-reflection region and a scattered-reflection region configuredto scattered-reflect the light.

A boundary region between the inclined plane and the flat surface may bea curved surface or includes a dihedral angle.

The first reflector may include a first region having the inclinedplane; and a second region having the flat surface, and the thickness ofa region adjacent to the light source module may be smaller than thethickness of a region distant from the light source module in the firstregion, or the thickness of the region adjacent to the light sourcemodule may be the same as the thickness of the region distant from thelight source module in the first region.

The first reflector may include a first region having the inclinedplane; and a second region having the flat surface, and the thickness ofa region adjacent to the light source module in the second region may belarger than the thickness of a region distant from the light sourcemodule, or the thickness of the region adjacent to the light sourcemodule may be the same as the thickness of the region distant from thelight source module in the second region.

A top surface of the first reflector may include a third regioncorresponding to an inclined plane disposed in a back surface of thefirst reflector; and a fourth region corresponding to a flat surfacedisposed in a back surface of the first reflector, and the third regionand the fourth region may not be collinear.

Here, the width of the third region may be different from the width ofthe fourth region. A surface of the third region and a surface of thefourth region may be curved or flat.

A reflection pattern may be formed on the flat surface disposed in theback surface of the first reflector.

Here, the reflection pattern may be saw-toothed and a surface of thereflection pattern is at least one of a flat surface, a concavely curvedsurface and a convexly curved surface. The size of the reflectionpattern may be irregular.

The size of the reflection pattern located adjacent to the light sourcemodule may be larger than the size of the reflection pattern locateddistant from the light source module.

The second reflector may include a first region and a second region, andthe first region may be aligned with the light source module and thefirst reflector and the first region is a first inclined plane inclineddownwardly, and the second region may be a flat surface in parallel to aflat surface disposed in a back surface of the first reflector or asecond inclined plane inclined upwardly.

Here, the flat surface disposed in the back surface of the firstreflector may be aligned in at least one of the first and second regionsdisposed in the second reflector.

The backlight unit may further include an optical member disposed aparta predetermined distance from the second reflector, wherein air guidemay be formed in a space formed between the second reflector and theoptical member.

Any reference in this specification to “one embodiment,” “anembodiment,” “example embodiment,” etc., means that a particularfeature, structure, or characteristic described in connection with theembodiment is included in at least one embodiment of the invention. Theappearances of such phrases in various places in the specification arenot necessarily all referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with any embodiment, it is submitted that it is within thepurview of one skilled in the art to effect such feature, structure, orcharacteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number ofillustrative embodiments thereof, it should be understood that numerousother modifications and embodiments can be devised by those skilled inthe art that will fall within the spirit and scope of the principles ofthis disclosure. More particularly, various variations and modificationsare possible in the component parts and/or arrangements of the subjectcombination arrangement within the scope of the disclosure, the drawingsand the appended claims. In addition to variations and modifications inthe component parts and/or arrangements, alternative uses will also beapparent to those skilled in the art.

What is claimed is:
 1. A lighting system comprising: a first reflector;a second reflector; and at least one light source module disposedbetween the first and second reflectors, wherein a surface of the firstreflector comprises an inclined plane and a flat surface, with facingthe second reflector, the inclined plane is adjacent to the light sourcemodule, and the flat surface is extended from an end of the inclinedplane, the second reflector comprises a first region and a secondregion, the first region is aligned with the light source module and thefirst reflector and the first region is a first inclined plane inclineddownwardly, and the second region is a flat surface in parallel to aflat surface disposed in a back surface of the first reflector or asecond inclined plane inclined upwardly.
 2. The lighting systemaccording to claim 1, wherein a top surface of the first reflectorcomprises a third region corresponding to an inclined plane disposed ina back surface of the first reflector and a fourth region correspondingto a flat surface disposed in a back surface of the first reflector, andthe third region and the fourth region include at least one projectionrespectively.
 3. The lighting system according to claim 2, wherein theat least one projection supports or couples optical members or panelguide molds.
 4. The lighting system according to claim 2, furthercomprising a plurality of hollownesses or minute projections formed in atop surface of the at least one projection.
 5. The lighting systemaccording to claim 1, further comprising plurality of reflectionpatterns formed on the flat surface, the reflection patterns aresaw-toothed, and a surface of the reflection patterns is flat, convexlycurved, or concavely curved.
 6. The lighting system according to claim5, wherein sizes of the plurality of reflection patterns are un-uniform.7. The lighting system according to claim 5, wherein a size of thereflection pattern located adjacent to the light source module is largerthan the size of the reflection pattern located distant from the lightsource module.
 8. The lighting system according to claim 1, wherein theat least one light source module contacts with the first reflector andthe second reflector.
 9. The lighting system according to claim 1,wherein at least one of the first inclined plane or the second inclinedplane are concavely curved.
 10. The lighting system according to claim1, wherein at least one of the first inclined plane or the secondinclined plane are convexly curved.
 11. The lighting system according toclaim 1, wherein the second reflector includes a metal material or ametal oxide selected from a group consisting of Al, Ag, Au and TiO_(2.)12. A lighting system comprising: a first reflector; a second reflector;and at least one light source module disposed between the first andsecond reflectors, wherein a surface of the first reflector comprises aninclined plane and a flat surface, with facing the second reflector, andthe inclined plane is adjacent to the light source module and the flatsurface is extended from an end of the inclined plane, and at least oneof the first reflector and the second reflector is spaced apart from thelight source module.
 13. The lighting system according to claim 12,wherein the light source module is spaced apart a first distance fromthe first reflector and a second distance from the second reflector, andthe first distance and the second distance is the same or different fromeach other.
 14. The lighting system according to claim 12, wherein thesecond reflector includes at least two inclined planes with at least oneinflection point, and curvatures of the two inclined planes aredifferent.
 15. The lighting system according to claim 12, wherein thesecond reflector includes a first region and a second region, aspecular-reflection sheet is formed on the first region, and at leastone of the specular-reflection sheet or a scatter-reflection sheet isformed on the second region.
 16. The lighting system according to claim12, further comprising plurality of reflection patterns formed on theflat surface, the reflection patterns are saw-toothed, and a surface ofthe reflection patterns is flat, convexly curved, or concavely curved.17. The lighting system according to claim 16, wherein sizes of theplurality of reflection patterns are un-uniform.
 18. The lighting systemaccording to claim 16, wherein a size of the reflection pattern locatedadjacent to the light source module is larger than the size of thereflection pattern located distant from the light source module.
 19. Thelighting system according to claim 12, wherein the light source modulecontacts with the first reflector and the second reflector.
 20. Alighting system comprising: a first reflector; a second reflector; andat least one light source module disposed between the first and secondreflectors, wherein a surface of the first reflector comprises aninclined plane and a flat surface, with facing the second reflector, andthe inclined plane is adjacent to the light source module and the flatsurface is extended from an end of the inclined plane, and the secondreflector comprises a first region and a second region, the first regionis aligned with the light source module and the first reflector and thefirst region is a first inclined plane inclined downwardly, the secondregion is a flat surface in parallel to a flat surface disposed in aback surface of the first reflector or a second inclined plane inclinedupwardly, and the light source module is spaced apart a first distancefrom the first reflector and a second distance from the secondreflector, and the first distance and the second distance is the same ordifferent from each other.